Solid pigment preparations containing water-soluble anionic surface-active additives that comprise carboxylate groups

ABSTRACT

Disclosed arm solid pigment preparations containing (A) 60 to 95 per weight of at least one pigment, (B) 5 to 40 percent by weight of at least one water-soluble anionic surface-active additive from the group of the homopolymers and copolymers of ethylenically unsaturated monocarboxylic acids and/or ethylenically unsaturated dicarboxylic acids which can additionally contain monopolymerized vinyl monomers having no acid function, the alkoxylation products of said homopolymers and copolymers, and the salts of said homopolymers and copolymers and the alkoxylation products thereof, and (C) 0 to 20 percent by weight of at least one nonionic surface-active polyether-based additive as essential components. Also disclosed are a method for the production thereof and methods for dyeing macromolecular organic and inorganic materials.

The present invention relates to solid pigment preparations comprisingas essential constituents

-   -   (A) from 60% to 95% by weight of at least one pigment,    -   (B) from 5% to 40% by weight of at least one water-soluble        anionic surface-active additive selected from the group of homo-        and copolymers of ethylenically unsaturated monocarboxylic acids        and/or ethylenically unsaturated dicarboxylic acids with or        without vinyl monomers comprising no acid function, alkoxylation        products of these homo- and copolymers and salts of these homo-        and copolymers and their alkoxylation products, and    -   (C) from 0% to 20% by weight of at least one nonionic        surface-active additive based on polyethers.

The present invention further relates to the production of these pigmentpreparations and to their use for pigmenting macromolecular organic andinorganic materials and also plastics.

Liquid systems such as coatings, varnishes, emulsion paints and printinginks are customarily colored using pigment formulations which comprisewater, organic solvent or mixtures thereof. As well as anionic,cationic, nonionic or amphoteric dispersants, these pigment formulationsgenerally have to be additized with further assistants, such asdried-crust inhibitors, freeze resistance enhancers, thickeners andanti-skinners, for stabilization.

There is a need for novel pigment preparations which are comparable tothe liquid formulations with regard to color properties anddispersibility, but do not require the additions mentioned and areeasier to handle. However, simply drying the liquid formulations doesnot provide solid pigment preparations having comparable performanceproperties.

The pigmentation of plastics requires complete dispersion of the pigmentin the plastic for the development of maximum color strength and coloreffect. For the pulverulent pigments typically used such dispersionrequires appropriate know-how and a high input of shearing energy andtherefore is costly. When the plastics processor does not possess thisknow-how and the requisite complicated and costly dispersion equipment,the pigmented plastics will often contain specks of incompletelydispersed pigment agglomerates, be difficult to spin and/or possess highpressure-filter values. Many plastics processors therefore employmasterbatches. A masterbatch is a typically solid, concentrated pigmentformulation in a plastics matrix which is solid at room temperature andmeltable and in which the pulverulent pigment is present in a stage ofcomplete dispersion and hence in a fine state of subdivision; that is,the energy needed to disperse the pulverulent pigment has already beeninvested to produce the masterbatch.

DE-A-39 14 384 describes pigment preparations which, as well as thefinely divided pigment (not less than 3.9% by weight), comprise basicpigment derivatives and (not more than 9.5% by weight) of phosphoricesters of polyethylene glycols and of alkylene oxide adducts with oxoprocess and fatty alcohols and are used for producing flowable printinginks and stock pastes.

EP-A-1 103 173, inter alia, mentions anionically modified phenol-styrenepolyglycol ethers as dispersants for solid pigment preparations used ascolorants for seed dressing. However, the explicitly disclosed pigmentpreparations only comprise nonionic dispersants based on reactionproducts of hydrogenated castor oil with ethylene oxide.

DE-A-100 35 494 discloses solid formulations of metal complex pigmentswith included melamine. Anionic, cationic, amphoteric and nonionicdispersants are mentioned as useful, but the dispersant actually used isa sulfated ethoxylated fatty alcohol.

DE-A-199 05 269 describes solid pigment formulations which comprisedispersants based on nonionic modified phenol-styrene polyglycol ethersor mixtures of ethoxylated castor oil with minor amounts of these ethersor of phosphonic esters and additionally always a thickener based onoptionally partially hydrogenated polyvinyl alcohol or on anionicpolyhydroxy compounds and are used for pigmenting waterborne applicationmedia.

EP-A-256 427 concerns pigment preparations for cosmetic articles thatcomprise mixtures of anionic dispersants based on alkylglycol ethersulfates and phosphoric esters of optionally ethoxylated fatty alcohols;the sulfates are always present in excess in the mixtures.

DE-A-102 27 657 and 102 33 081, which were unpublished at the prioritydate of the present invention, disclose solid pigment preparations whichcomprise anionic surface-active additives based on phosphoric,phosphonic, sulfuric and/or sulfonic esters of polyethers and theirsalts and also their use for pigmentation of macromolecular organic andinorganic materials and also plastics.

EP-A-58 865 discloses pigment formulations which are prepared byprecipitating water-insoluble salts of anionic polymers with polyvalentmetal cations onto the pigment particles.

It is an object of the present invention to provide solid pigmentpreparations having altogether advantageous application properties,especially high color strength and particularly good dispersibility in awide variety of application media.

We have found that this object is achieved by pigment preparationscomprising as essential constituents

-   -   (A) from 60% to 95% by weight of at least one pigment,    -   (B) from 5% to 40% by weight of at least one water-soluble        anionic surface-active additive selected from the group of homo-        and copolymers of ethylenically unsaturated monocarboxylic acids        and/or ethylenically unsaturated dicarboxylic acids with or        without vinyl monomers comprising no acid function, alkoxylation        products of these homo- and copolymers and salts of these homo-        and copolymers and their alkoxylation products, and    -   (C) from 0% to 20% by weight of at least one nonionic        surface-active additive based on polyethers.

The present invention further provides a process for producing pigmentpreparations, which comprises wet-comminuting the pigment (A) in aqueoussuspension in the presence of some or all of additive (B) and optionally(C) and then drying the suspension, if necessary after the rest ofadditive (B) and optionally (C) has been added.

The present invention yet further provides a process for pigmentingmacromolecular organic and inorganic materials, which comprisesincorporating pigment preparations in these materials by stirring orshaking.

The present invention finally provides a process for pigmentingplastics, which comprises incorporating these pigment preparations inthe plastics by extrusion, rolling, kneading or grinding.

The pigment preparations of the present invention comprise as essentialconstituents a pigment (A) and a water-soluble anionic surface-activeadditive (B) and also, if desired, a nonionic additive (C).

Component (A) in the pigment preparations of the present invention maybe an organic pigment or an inorganic pigment. It will be appreciatedthat the pigment preparations may also comprise mixtures of variousorganic or various inorganic pigments or mixtures of organic andinorganic pigments.

The pigments are present in finely divided form. Accordingly thepigments typically have average particle sizes from 0.1 to 5 μm.

The organic pigments are typically organic chromatic and black pigments.Inorganic pigments can likewise be color pigments (chromatic, black andwhite pigments) and also luster pigments and the inorganic pigmentstypically used as fillers.

There now follow examples of suitable organic color pigments: monoazopigments: C.I. Pigment Brown 25; C.I. Pigment Orange 5, 13, 36, 38, 64and 67; C.I. Pigment Red 1, 2, 3, 4, 5, 8, 9, 12, 17, 22, 23, 31, 48:1,48:2, 48:3, 48:4, 49, 49:1, 51:1, 52:1, 52:2, 53, 53:1, 53:3, 57:1,58:2, 58:4, 63, 112, 146, 148, 170, 175, 184, 185, 187, 191:1, 208, 210,245, 247 and 251; C.I. Pigment Yellow 1, 3, 62, 65, 73, 74, 97, 120,151, 154, 168, 181, 183 and 191; C.I. Pigment Violet 32; disazopigments: C.I. Pigment Orange 16, 34, 44 and 72; C.I. Pigment Yellow 12,13, 14, 16, 17, 81, 83, 106, 113, 126, 127, 155, 174, 176, 180 and 188;disazo condensation pigments: C.I. Pigment Yellow 93, 95 and 128; C.I.Pigment Red 144, 166, 214, 220, 221, 242 and 262; C.I. Pigment Brown 23and 41; anthanthrone pigments: C.I. Pigment Red 168; anthraquinonepigments: C.I. Pigment Yellow 147, 177 and 199; C.I. Pigment Violet 31;anthrapyrimidine pigments: C.I. Pigment Yellow 108; quinacridonepigments: C.I. Pigment Orange 48 and 49; C.I. Pigment Red 122, 202, 206and 209; C.I. Pigment Violet 19; quinophthalone pigments: C.I. PigmentYellow 138; diketopyrrolopyrrole pigments: C.I. Pigment Orange 71, 73and 81; C.I. Pigment Red 254, 255, 264, 270 and 272; dioxazine pigments:C.I. Pigment Violet 23 and 37; C.I. Pigment Blue 80; flavanthronepigments: C.I. Pigment Yellow 24; indanthrone pigments: C.I. PigmentBlue 60 and 64; isoindoline pigments: C.I. Pigments Orange 61 and 69;C.I. Pigment Red 260; C.I. Pigment Yellow 139 and 185; isoindolinonepigments: C.I. Pigment Yellow 109, 110 and 173; isoviolanthronepigments: C.I. Pigment Violet 31; metal complex pigments: C.I. PigmentRed 257; C.I. Pigment Yellow 117, 129, 150, 153 and 177; C.I. PigmentGreen 8; perinone pigments: C.I. Pigment Orange 43; C.I. Pigment Red194; perylene pigments: C.I. Pigment Black 31 and 32; C.I. Pigment Red123, 149, 178, 179, 190 and 224; C.I. Pigment Violet 29; phthalocyaninepigments: C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6 and 16;C.I. Pigment Green 7 and 36; pyranthrone pigments: C.I. Pigment Orange51; C.I. Pigment Red 216; pyrazoloquinazolone C.I. Pigment Orange 67;pigments: C.I. Pigment Red 251; thioindigo pigments: C.I. Pigment Red 88and 181; C.I. Pigment Violet 38; triarylcarbonium pigments: C.I. PigmentBlue 1, 61 and 62; C.I. Pigment Green 1; C.I. Pigment Red 81, 81:1 and169; C.I. Pigment Violet 1, 2, 3 and 27;C.I. Pigment Black 1 (aniline black);C.I. Pigment Yellow 101 (aldazine yellow);C.I. Pigment Brown 22.

Examples of suitable inorganic color pigments are: white titaniumdioxide (C.I. Pigment White 6), zinc white, pigment pigments: grade zincoxide; zinc sulfide, lithopone; black iron oxide black (C.I. PigmentBlack 11), pigments: iron manganese black, spinel black (C.I. PigmentBlack 27); carbon black (C.I. Pigment Black 7); chromatic chromiumoxide, chromium oxide hydrate green; chrome pigments: green (C.I.Pigment Green 48); cobalt green (C.I. Pigment Green 50); ultramarinegreen; cobalt blue (C.I. Pigment Blue 28 and 36; C.I. Pigment Blue 72);ultramarine blue; manganese blue; ultramarine violet; cobalt violet andmanganese violet; red iron oxide (C.I. Pigment Red 101); cadmiumsulfoselenide (C.I. Pigment Red 108); cerium sulfide (C.I. Pigment Red265); molybdate red (C.I. Pigment Red 104); ultramarine red; brown ironoxide (C.I. Pigment Brown 6 and 7), mixed brown, spinel phases andcorundum phases (C.I. Pigment Brown 29, 31, 33, 34, 35, 37, 39 and 40),chromium titanium yellow (C.I. Pigment Brown 24), chrome orange; ceriumsulfide (C.I. Pigment Orange 75); yellow iron oxide (C.I. Pigment Yellow42); nickel titanium yellow (C.I. Pigment Yellow 53; C.I. Pigment Yellow157, 158, 159, 160, 161, 162, 163, 164 and 189); chromium titaniumyellow; spinel phases (C.I. Pigment Yellow 119); cadmium sulfide andcadmium zinc sulfide (C.I. Pigment Yellow 37 and 35); chrome yellow(C.I. Pigment Yellow 34); bismuth vanadate (C.I. Pigment Yellow 184).

Examples of inorganic pigments typically used as fillers are transparentsilicon dioxide, ground quartz, aluminum oxide, aluminum hydroxide,natural micas, natural and precipitated chalk and barium sulfate.

Luster pigments are platelet-shaped pigments having a monophasic orpolyphasic construction whose color play is marked by the interplay ofinterference, reflection and absorption phenomena. Examples are aluminumplatelets and aluminum, iron oxide and mica platelets bearing one ormore coats, especially of metal oxides.

Component (B) of the solid pigment preparations according to the presentinvention is at least one water-soluble anionic surface-active additiveselected from the group of homo- and copolymers of ethylenicallyunsaturated monocarboxylic acids and/or ethylenically unsaturateddicarboxylic acids with or without vinyl monomers comprising no acidfunction, alkoxylation products of these homo- and copolymers and saltsof these homo- and copolymers and their alkoxylation products.

Examples of the carboxyl-containing monomers and of the vinyl monomersare:

-   -   acrylic acid, methacrylic acid and crotonic acid;    -   maleic acid, maleic anhydride, maleic monoesters, maleic        monoamides, reaction products of maleic acid with diamines which        may have been oxidized to derivatives containing amine oxide        groups, and fumaric acid, of which maleic acid, maleic anhydride        and maleic monoamides are preferred;    -   styrenics, such as styrene, methylstyrene and vinyltoluene;        ethylene, propylene, isobutene, diisobutene and butadiene; vinyl        ethers, such as polyethylene glycol monovinyl ether; vinyl        esters of linear or branched monocarboxylic acids, such as vinyl        acetate and vinyl propionate; alkyl esters and aryl esters of        ethylenically unsaturated monocarboxylic acids, especially        acrylic and methacrylic esters, such as methyl, ethyl, propyl,        isopropyl, butyl, pentyl, hexyl, 2-ethylhexyl, nonyl, lauryl or        hydroxyethyl (meth)acrylate and also phenyl, naphthyl or benzyl        (meth)acrylate; dialkyl esters of ethylenically unsaturated        dicarboxylic acids, such as dimethyl, diethyl, dipropyl,        diisopropyl, dibutyl, dipentyl, dihexyl, di-2-ethylhexyl,        dinonyl, dilauryl or di-2-hydroxyethyl maleate or fumarate;        vinylpyrrolidone; acrylonitrile and methacrylonitrile, of which        styrene, isobutene, diisobutene, acrylic esters and polyethylene        glycol monovinyl ether are preferred.

Preferred homopolymers of these monomers are in particular polyacrylicacids, for example. The copolymers of the monomers mentioned may becopolymerized from two or more and especially from three differentmonomers. The copolymers may be random copolymers, alternatingcopolymers, block copolymers or graft copolymers. Preferred copolymersare stryene-acrylic acid, acrylic acid-maleic acid, acrylicacid-methacrylic acid, butadiene-acrylic acid, isobutene-maleic acid,diisobutene-maleic acid, and styrene-maleic acid copolymers, which mayeach additionally comprise units derived from acrylic ester and/ormaleic ester monomer.

Preferably, the carboxyl groups of nonalkoxylated homo- and copolymersare at least partly present in salt form in order that solubility inwater may be ensured. Useful salts include alkali metal salts, such assodium and potassium salts, and ammonium salts.

Typically, nonalkoxylated polymeric additives (B) have average molecularweights M_(w) in the range from 900 to 250 000. Since the molecularweight ranges which are particularly suitable for the individualaddition polymers depend on their composition, as will be appreciated.The molecular weights will now be specified for various polymers by wayof example: polyacrylic acids: M_(w) from 900 to 250 000;styrene-acrylic acid copolymers: M_(w) from 1000 to 50 000; acrylicacid-methacrylic acid copolymers: M_(w) from 1000 to 250 000; acrylicacid-maleic acid copolymers: M_(w) from 2000 to 70 000.

As well as the carboxyl-containing polymers themselves, theiralkoxylation products are likewise of particular interest for use as (B)additives.

By alkoxylation products of the carboxyl-containing polymers are meantherein for the purposes of the present invention in particular thepolymers after partial or (insofar as possible) full esterification withpolyether alcohols. Generally, the degree of esterification of thesepolymers is in the range from 30 to 80 mol %.

The esterification may usefully be carried out in particular with thepolyether alcohols themselves, preferably polyethylene glycols andpolypropylene glycols, and also their singly tipped derivatives, inparticular the corresponding monoethers, such as monoaryl ethers, egmonophenyl ether, and especially mono-C₁-C₂₆-alkyl ethers, for examplefatty alcohol etherified ethylene and propylene glycols, and thepolyether amines which are preparable for example by conversion of aterminal OH group of the corresponding polyether alcohols or bypolyaddition of alkylene oxides onto preferably primary aliphaticamines. Preference is here given to polyethylene glycols, polyethyleneglycol monoether and polyether amines. The average molecular weightsM_(n) of the polyether alcohols used and their derivatives are typicallyin the range from 200 to 10 000.

By controlling the ratio of polar to apolar groups it is possible totune the surface-active properties of the (B) additives in aspecifically targeted manner.

Such anionic surface-active additives (B) are likewise known andcommercially available for example under the names of Sokalan® (BASF),Joncryl® (Johnson Polymer), Alcosperse® (ALco), Geropon® (Rhodia),Good-Rite® (Goodrich), Neoresin® (Avecia), Orotan® and Morez® (Rohm &Haas), Disperbyk® (Byk) and also Tegospers® (Goldschmidt).

The pigment preparations according to the present invention mayadditionally comprise nonionic surface-active additives based onpolyethers as a component (C).

As well as unmixed polyalkylene oxides, preferably C₂-C₄-alkylene oxidesand phenyl-substituted C₂-C₄-alkylene oxides, in particular polyethyleneoxides, polypropylene oxides and poly(phenylethylene oxide)s, it isparticularly block copolymers, in particular suitability comprisingpolypropylene oxide and polyethylene oxide blocks or else poly(phenyleneoxide) and polyethylene oxide blocks, but also random copolymers ofthese alkylene oxides which are useful.

They, like the unmixed polyalkylene oxides, are obtainable bypolyaddition of alkylene oxides to starter molecules, such as saturatedor unsaturated aliphatic and aromatic alcohols, phenol or naphthol,which can be substituted by alkyl, in particular C₁-C₁₂ alkyl,preferably C₄-C₁₂ or C₁-C₄ alkyl, saturated or unsaturated aliphatic andaromatic amines, saturated or unsaturated aliphatic carboxylic acids andcarboxamides. It is customary to use from 1 to 300 mol and preferablyfrom 3 to 150 mol of alkylene oxide per mole of starter molecule.

Suitable aliphatic alcohols comprise in general from 6 to 26 carbonatoms and preferably from 8 to 18 carbon atoms and can have anunbranched, branched or cyclic structure. Examples are octanol, nonanol,decanol, isodecanol, undecanol, dodecanol, 2-butyloctanol, tridecanol,isotridecanol, tetradecanol, pentadecanol, hexadecanol (cetyl alcohol),2-hexyldecanol, heptadecanol, octadecanol, (stearyl alcohol),2-heptylundecanol, 2-octyidecanol, 2-nonyltridecanol,2-decyltetradecanol, oleyl alcohol and 9-octadecenol and also mixturesof these alcohols, such as C₈/C₁₀, C₁₃/C₁₅ and C₁₆/C₁₈ alcohols, andcyclopentanol and cyclohexanol. Of particular interest are the saturatedor unsaturated fatty alcohols obtained from natural raw materials by fathydrolysis and reduction and the synthetic fatty alcohols from the oxoprocess. The alkylene oxide adducts with these alcohols typically haveaverage molecular weights M_(n) from 200 to 5 000.

Examples of the abovementioned aromatic alcohols include not onlyunsubstituted phenol and □- and □-naphthol but also hexylphenol,heptylphenol, octylphenol, nonylphenol, isononylphenol, undecylphenol,dodecylphenol, di- and tributylphenol and dinonylphenol.

Suitable aliphatic amines correspond to the abovementioned aliphaticalcohols. Again of particular importance here are the saturated andunsaturated fatty amines which preferably have from 14 to 20 carbonatoms. Examples of suitable aromatic amines are aniline and itsderivatives.

Useful aliphatic carboxylic acids include especially saturated andunsaturated fatty acids which preferably contain from 14 to 20 carbonatoms and fully hydrogenated, partially hydrogenated and unhydrogenatedresin acids and also polyfunctional carboxylic acids, for exampledicarboxylic acids, such as maleic acid.

Suitable carboxamides are derived from these carboxylic acids.

As well as alkylene oxide adducts with monofunctional amines andalcohols it is alkylene oxide adducts with at least bifunctional aminesand alcohols which are of very particular interest.

The at least bifunctional amines preferably have from 2 to 5 aminegroups and conform in particular to the formula H₂N—(R—NR′)_(n)—H (R:C₂-C₆-alkylene; R¹: hydrogen or C₁-C₆-alkyl; n: 1-5).

Specific examples are: ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, 1,3-propylenediamine,dipropylenetriamine, 3-amino-1-ethylene-aminopropane,hexamethylenediamine, dihexamethylenetriamine,1,6bis(3-aminopropyl-amino)hexane and N-methyidipropylenetriamine, ofwhich hexamethylenediamine and diethylenetriamine are more preferableand ethylenediamine is most preferable.

These amines are preferably reacted first with propylene oxide and thenwith ethylene oxide. The ethylene oxide content of the block copolymersis typically about 10-90% by weight.

The average molecular weights M_(n) of the block copolymers based onpolyamines are generally in the range from 1 000 to 40 000 andpreferably in the range from 1 500 to 30 000.

The at least bifunctional alcohols preferably have from two to fivehydroxyl groups. Examples are C₂-C₆-alkylene glycols and thecorresponding di- and polyalkylene glycols, such as ethylene glycol,1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol,1,4-butylene glycol, 1,6-hexylene glycol, dipropylene glycol andpolyethylene glycol, glycerol and pentaerythritol, of which ethyleneglycol and polyethylene glycol are more preferable and propylene glycoland dipropylene glycol are most preferable.

Particularly preferred alkylene oxide adducts with at least bifunctionalalcohols have a central polypropylene oxide block, ie are based on apropylene glycol or polypropylene glycol which is initially reacted withfurther propylene oxide and then with ethylene oxide. The ethylene oxidecontent of the block copolymers is typically in the range from 10% to90% by weight.

The average molecular weights M_(n) of the block copolymers based onpolyhydric alcohols are generally in the range from 1 000 to 20 000 andpreferably in the range from 1 000 to 15 000.

Such alkylene oxide block copolymers are known and commerciallyavailable for example under the names of Tetronic® and Pluronic® (BASF).

The pigment preparations of the present invention comprise from 60% to95% by weight of component (A), from 5% to 40% by weight of component(B) and from 0% to 20% by weight of component (C).

When the pigment preparations of the present invention do not compriseany nonionic additive (C), the preferred compositions depend on the typeof pigment they comprise:

from 70% to 90% by weight and especially from 70% to 85% by weight oforganic pigment (A) and from 10% to 30% by weight and especially from15% to 30% by weight of additive (B); from 60% to 80% by weight andespecially from 60% to 75% by weight of transparent iron oxide pigment(A) and from 20% to 40% by weight and especially from 25% to 40% byweight of additive (B);

from 70% to 95% by weight and especially from 75% to 95% by weight ofinorganic pigment (A) (other than transparent iron oxide pigment) andfrom 5% to 30% by weight and especially from 5% to 25% by weight ofadditive (B).

When a nonionic additive (C) is comprised, the composition of thepigment preparations according to the present invention is preferablyfrom 60% to 85% by weight of pigment (A), from 5% to 20% by weight ofanionic additive (B) and from 5% to 15% by weight of nonionic additive(C).

The pigment preparations of the present invention are advantageouslyobtainable by the production process of the present invention bywet-comminuting the pigment (A) in aqueous suspension in the presence ofsome or all of additive (B) and optionally (C) and then drying thesuspension, if necessary after the rest of additive (B) and optionally(C) has been added.

Pigment (A) can be used in the process of the present invention as a drypowder or in the form of a presscake.

The pigment (A) used is preferably a finished product, ie the primaryparticle size of the pigment has already been adjusted to the desiredapplication value. This finish is advisable in the case of organicpigments especially, since the as-synthesized crude material isgenerally not directly suitable for use. In the case of inorganicpigments, for example in the case of oxide and bismuth vanadatepigments, the primary particle size can also be adjusted in the courseof the synthesis of the pigment, so that the as-synthesized pigmentsuspensions can be used directly for producing the pigment preparationsto be used according to the present invention.

Since the finished pigment (A) typically reagglomerates in the course ofdrying or on the filter assembly, it is subjected to wet comminution inaqueous suspension, eg grinding in a stirred media mill.

The wet comminution should be carried out in the presence of at least aportion of the additive (B and optionally C) comprised in theready-produced pigment preparation, and it is preferable to add theentire amount of additive (B and optionally C) prior to the wetcomminution.

The particle size of the pigment preparations of the present inventioncan be controlled to a specific value, depending on the chosen method ofdrying the aqueous pigment suspension—spray granulation and fluidizedbed drying, spray drying, drying in a paddle dryer, evaporation andsubsequent comminution.

Spray and fluidized bed granulation may produce coarsely dividedgranules having average particle sizes from 50 to 5 000 μm, andespecially from 100 to 1 000 μm. Spray drying typically producesgranules having average particle sizes <20 μm. Finely dividedpreparations are obtainable by drying in a paddle dryer and byevaporation with subsequent grinding. Preferably, however, the pigmentpreparations of the present invention are in granule form.

Spray granulation is preferably carried out in a spray tower using aone-material nozzle. Here, the suspension is sprayed in the form ofrelatively large drops, and the water evaporates. The additives melt atthe drying temperatures and so lead to the formation of a substantiallyspherical granule having a particularly smooth surface (BET valuesgenerally □15 m²/g, and especially □m²/g).

The gas inlet temperature in the spray tower is generally in the rangefrom 180 to 300° C. and preferably in the range from 150 to 300° C. Thegas outlet temperature is generally in the range from 70 to 150° C. andpreferably in the range from 70 to 130° C.

The residual moisture content of the granular pigment obtained ispreferably <2% by weight.

The pigment preparations of the present invention are notable in use inapplication media having a liquid phase for their excellent colorproperties which are comparable to those of liquid pigment formulations,especially with regard to color strength, brilliance, hue and hidingpower, and in particular for their stir-in characteristics, ie they canbe dispersed in application media with a minimal input of energy, simplyby stirring or shaking. This applies in particular to the coarselydivided pigment granules, which constitute the preferred embodiment ofthe pigment preparations of the present invention.

Compared with liquid pigment formulations, the pigment preparations ofthe present invention additionally have the following advantages: Theyhave a higher pigment content. Whereas liquid formulations tend tochange viscosity during storage and have to be admixed withpreservatives and agents for enhancing the resistance to freezing and/ordrying out (crusting), the pigment preparations of the present inventionexhibit very good stability in storage. They are both economically andecologically advantageous with regard to packaging, storage andtransportation. Since they are solvent free, they are more flexible inuse.

The pigment preparations of the present invention which are in granuleform are notable for excellent attrition resistance, a minimal tendencyto compact or clump, uniform particle size distribution, goodpourability, flowability and meterability and also dustlessness inhandling and application.

The pigment preparations of the present invention are very useful forpigmenting macromolecular organic and inorganic materials of any kind.Liquid application media in this context can be purely aqueous; comprisemixtures of water and organic solvents, for example alcohols; or bebased exclusively on organic solvents, such as alcohols, glycol ethers,ketones, eg methyl ethyl ketone, amides, eg N-methylpyrrolidone anddimethylformamide, esters, eg ethyl acetate, butyl acetate andmethoxypropyl acetate, or aromatic or aliphatic hydrocarbons, eg xylene,mineral oil and mineral spirits.

If desired, the preparations can initially be stirred into a solventwhich is compatible with the particular application medium, again withminimal input of energy, and then be introduced into this applicationmedium. For instance, slurries of pigment preparations in glycols orother solvents customary in the paint and coatings industry, such asmethoxypropyl acetate, can be used to render the pigment preparationsfor aqueous systems compatible with hydro-carbonaceous systems orsystems based on nitrocellulose.

Examples of materials which can be pigmented with the pigmentpreparations of the present invention include: coatings, for examplearchitectural coatings, industrial coatings, automotive coatings,radiation-curable coatings; paints, including paints for buildingexteriors and building interiors, for example wood paints, lime washes,distempers, emulsion paints; solventborne printing inks, for exampleoffset printing inks, flexographic printing inks, toluene gravureprinting inks, textile printing inks, radiation-curable printing inks;waterborne inks, including inkjet inks; color filters; buildingmaterials (water is typically added only after building material andgranular pigment have been dry mixed), for example silicate rendersystems, cement, concrete, mortar, gypsum; bitumen, caulks; cellulosicmaterials, for example paper, paperboard, cardboard, wood and woodbase,which can each be coated or otherwise finished; adhesives; film-formingpolymeric protective colloids as used for example in the pharmaceuticalindustry; cosmetic articles; detergents.

The pigment preparations of the invention are very useful for coloringplastics. The following classes and types of plastics may be mentionedby way of example:

-   -   modified natural materials:    -   thermosets, eg casein plastics; thermoplastics, eg cellulose        nitrate, cellulose acetate, cellulose mixed esters and cellulose        ethers;    -   synthetic plastics:    -   polycondensates: thermosets, eg phenolic resin, urea resin,        thiourea resin, melamine resin, unsaturated polyester resin,        allylic resin, silicone, polyimide and polybenzimidazole;        thermoplastics, eg polyamide, polycarbonate, polyester,        polyphenylene oxide, polysulfone and polyvinyl acetal;    -   addition polymers: thermoplastics, eg polyolefins, such as        polyethylene, polypropylene, poly-1-butene and        poly-4-methyl-1-pentene, ionomers, polyvinyl chloride,        polyvinylidene chloride, polymethyl methacrylate,        polyacrylonitrile, polystyrene, polyacetal, fluoropolymers,        polyvinyl alcohol, polyvinyl acetate and poly-p-xylylene and        also copolymers, such as ethylene-vinyl acetate copolymers,        styrene-acrylonitrile copolymers,        acrylonitrile-butadiene-styrene copolymers, polyethylene glycol        terephthalate and polybutylene glycol terephthalate;

polyadducts: thermosets, eg epoxy resin and crosslinked polyurethanes;thermoplastics, eg linear polyurethanes and chlorinated polyethers.

Advantageously, plastics are colorable with the pigment preparations ofthe invention by minimal energy input, for example by conjoint extrusion(preferably using a single- or twin-screw extruder), rolling, kneadingor grinding. The plastics can be present at that stage as plasticallydeformable masses or melts and be processed into moldings, film andfiber.

The solid pigment preparations to be used according to the presentinvention are additionally notable in coloring plastics for altogetheradvantageous application properties, especially for good colorproperties, in particular high color strength and brilliance, and thegood rheological properties of the plastics which have been colored withthem, especially for low pressure-filter values (high filter lifetimes)and good spinnability.

EXAMPLES

Production and testing of pigment preparations according to the presentinvention

The pigment preparations were produced by a suspension of x g offinished pigment (A), y g of additive (B) and optionally z g of additive(C) in 150 g of water (if pH □7, adjusted to pH=7 by addition of 25% byweight aqueous sodium hydroxide solution) being ball milled to a d₅₀value of □1 μm and then spray dried in a laboratory spray tower (MiniSpray Dryer B-191, from Büchi; gas inlet temperature 170° C., gas outlettemperature 70° C.).

The color strength of the pigment preparations was determinedcolorimetrically in white reduction (reported in terms of the DIN 55986coloring equivalents CEs) in a waterborne emulsion paint. To this end, amixture of in each case 1.25 g of pigment preparation and 50 g of awaterborne styrene/acrylate-based test binder having a white pigmentcontent of 16.4% by weight (TiO₂, Kronos 2043) (BASF test binder00-1067) were homogenized in a 150 ml plastic cup by running a highspeed stirrer at 1500 rpm for 3 min. The color obtained was then drawndown on a black and white test card using a 100 μm wire-wound filmapplicator and dried for 30 min.

The pigment preparations of the present invention exhibited colorstrengths which were comparable to those of the respective analogouscommercially available aqueous formulations of the pigments.

The table hereinbelow lists the compositions of the pigment preparationsproduced. The content of the additives (B) and (C) is based on thedissolved polymer when the polymers were used in solution. The additives(B) and (C) used were as follows:

B1: aqueous solution of a copolymer of 50% by weight maleic anhydrideand 50% by weight diisobutene (solids content: 25%; pH:10; M_(w): 12000)

B2: aqueous solution of polyacrylic acid (solids content: 45%; pH:8.5;M₂: 4000)

B3: aqueous solution of a copolymer of 70% by weight of methacrylic acidand 30% by weight of acrylic acid (solids content: 25%; pH:2; M_(w): 20000)

B4: aqueous solution of a copolymer of 70% by weight acrylic acid and30% by weight maleic anhydride (solids content: 90%; pH:8; M_(w): 70000)

B5: aqueous solution of a 50% be weight maleic anhydride and 50% byweight isobutene compolymer reacted with ethoxylated C₁₂/C₁₄fattyalcohol (7 EO/mol of alcohol) (solids content: 45%; pH:7.5; M_(w): 3000)

B6: aqueous solution of a polymethacrylic acid reacted withpo.lyethylene glycol (M_(n) 1000) (solids content: 40%; pH:7; M_(w): 20000)

B7: aqueous solution of a copolymer of 30% by weight isobutene and 70%by weight maleic anhydride (solids content: 44%; pH:7.5; M_(w): 4000)

B8: aqueous solution of polyacrylic acid (solids content: 45%; pH:8;M_(w): 1000)

B9: aqueous solution of polyacrylic acid (solids content: 45%; pH:8;M_(w): 30 000)

B10: aqueous solution of the 50% by weight styrene and 50% by weightmaleic anydride copolymer reacted with polyethylene glycol (M_(n) 500)(solids content: 43%; pH:8; M_(w): 10 000)

B11: aqueous solution of a copolymer of 50 mol% maleic anhydride and 50mol% vinyl polyethylene oxide (solids content: 40%; pH:7; M_(w):20 000)

B12: aqueous solution of a copolymer of 40 mol% isobutene, 47 mol%maleic acid and 3 mol% C₁₈ olefin (solids content: 25%; pH:8; M_(w):10000)

C: ethylenediamine/propylene oxide/ethylene oxide block copolymer havingan ethylene oxide content of 40% by weight and an average molecularweight M_(n) of 12 000 TABLE Pigment Additive Additive (C) Ex. (A) x g(B) y g z g 1 P.Y. 184 90 B4 10 — 2 P.Y. 184 87.5 B1 12.5 — 3 P.Y. 18487.5 B2 12.5 — 4 P.Y. 184 85 B3 15 — 5 P.Y. 184 85 B8 15 — 6 P.Y. 184 85B9 15 — 7 P.Y. 184 85 B5 15 — 8 P.Y. 184 85 B6 15 — 9 P.Y. 184 90 B10 10— 10 P.Y. 184 85 B10 15 — 11 P.Y. 184 85 B10 7.5 7.5 12 P.Y. 184 80 B1020 — 13 P.Y. 184 85 B12 15 — 14 P.Y. 184 85 B11 15 — 15 P.Br. 24 90 B410 — 16 P.Br. 24 87.5 B1 12.5 — 17 P.Br. 24 87.5 B2 12.5 — 18 P.Br. 2485 B3 15 — 19 P.Br. 24 85 B8 15 — 20 P.Br. 24 85 B9 15 — 21 P.Br. 24 85B7 15 — 22 P.Br. 24 85 B5 15 — 23 P.Br. 24 85 B6 15 — 24 P.Br. 24 92.5B10 7.5 — 25 P.Br. 24 90 B10 10 — 26 P.Br. 24 85 B10 15 — 27 P.Br. 24 85B10 7.5 7.5 28 P.Br. 24 80 B10 20 — 29 P.Br. 24 85 B12 15 — 30 P.Br. 2485 B11 15 — 31 P.Y. 42 87.5 B2 12.5 — 32 P.Y. 42 90 B10 10 — 33 P.Y. 4290 B10 5 5   34 P.Y. 42 85 B10 15 — 35 P.Y. 42 80 B10 20 — 36 P.Y. 42 85B12 15 — 37 P.Y. 42 85 B11 15 — 38 P.R. 101 87.5 B2 12.5 — 39 P.R. 10190 B10 10 — 40 P.R. 101 85 B10 15 — 41 P.R. 101 80 B10 20 — 42 P.R. 10185 B12 15 — 43 P.R. 101 85 B12 7.5 7.5 44 P.R. 101 85 B11 15 — 45 P.Y.42 70 B2 30 — 46 P.Y. 42 70 B10 30 — 47 P.Y. 42 65 B10 35 — 48 P.Y. 4270 B11 30 — 49 P.Y. 42 65 B11 35 — 50 P.B. 15:1 75 B10 25 — 51 P.B. 15:175 B10 12.5 12.5  52 P.B. 15:3 75 B10 25 — 53 P.B. 15:3 75 B10 12.512.5  54 P.R. 112 75 B10 25 — 55 P.R. 112 75 B10 12.5 12.5  56 P.R. 11275 B1 25 — 57 P.Y. 74 75 B1 25 —

1. A solid pigment preparation comprising (A) from 60% to 95% by weightof at least one pigment, (B) from 5% to 40% by weight of at least onewater-soluble anionic surface-active additive selected from the groupconsisting of homo- and copolymers of ethylenically unsaturatedmonocarboxylic acids and/or ethylenically unsaturated dicarboxylic acidswith or without vinyl monomers comprising no acid function, alkoxylationproducts of these homo- and copolymers and salts of these homo- andcopolymers and their alkoxylation products, and (C) from 0% to 20% byweight of at least one nonionic surface-active additive based onpolyethers.
 2. A solid pigment preparation as claimed in claim 1, in theform of granules having an average particle size from 50 to 5000 μm anda BET surface area of ≦15 m²/g.
 3. A process for producing pigmentpreparations as claimed in claim 1, which comprises wet-comminuting thepigment (A) in aqueous suspension in the presence of some or all ofadditive (B) and optionally (C) and then drying the suspension, ifnecessary after the rest of additive (B) and optionally (C) has beenadded.
 4. A process for pigmenting macromolecular organic and inorganicmaterials, which comprises incorporating pigment preparations as claimedin claim 1 in these materials by stirring or shaking.
 5. A process asclaimed in claim 4, for pigmenting coatings, paints, inks, includingprinting inks, and finish systems where the liquid phase compriseswater, organic solvents or mixtures of water and organic solvents.
 6. Aprocess for pigmenting plastics, which comprises incorporating pigmentpreparations as claimed in claim 1 in the plastics by extrusion,rolling, kneading or grinding.